Charleston Lowcountry · gathered 13 September 2026
Tankless Water Heater Cost in Charleston SC (2026)
Real published numbers with the source beside each one. Five companies in two metros publish any.
Real published numbers with the source beside each one. Five companies in two metros publish any.
Quick answer: In Charleston, published local prices are $2,850 to $4,500 to install a new gas tankless water heater and $1,950 to $3,800 to replace an existing one, with a Summerville company publishing $3,000 to $6,500+ for a whole-home unit. A 50-gallon tank replacement, for comparison, is $1,550 to $2,800. The difference is almost entirely the gas line, the vent and the condensate drain, because a whole-house gas tankless unit burns about five times the gas of the tank it replaces. These are published market ranges gathered 13 September 2026, not our quote.
Almost nobody in this market publishes a tankless price. Of the plumbing and home services companies checked across the Charleston metro, three publish an installed number on their own website; the rest advertise transparent pricing and publish nothing.
So this page collects what is published — locally first, then nationally, then the adders that decide which end of the range your house lands on — and puts the source and the date next to every figure so you can check any of them.
| Job | Published price | Source |
|---|---|---|
| Tankless, new installation (natural gas) | $2,850 – $4,500 | Swell Guy Plumbing Co. — tankless installation · 2026 — Rinnai and Navien |
| Tankless, replacing an existing tankless | $1,950 – $3,800 | Swell Guy Plumbing Co. — tankless installation · 2026 — the gas line and vent already exist |
| Tankless, whole-home | $3,000 – $6,500+ | Pineapple Plumbing, Summerville — published plumber costs · 2026-08-22 — published 22 August 2026 |
| 40–50 gallon tank, for comparison | $1,800 – $3,000 | Pineapple Plumbing, Summerville — published plumber costs · 2026-08-22 |
| 50 gallon tank, for comparison | $1,550 – $2,800 | Swell Guy Plumbing Co. published price ranges · 2026 — State and A.O. Smith |
| Descaling flush | $185 | Swell Guy Plumbing Co. published price ranges · 2026 — annual maintenance |
| Descale, flush, filter and safety inspection | $249 | Coastal Flow Solutions — Charleston tankless service · 2026 |
| Gas line installation | from $750 | Swell Guy Plumbing Co. published price ranges · 2026 — per foot, 50 ft minimum, permit required |
| Gas safety test / meter reconnect | $350 – $550 | Swell Guy Plumbing Co. published price ranges · 2026 — permit fees vary by municipality |
| Water heater repair — relief valves, expansion tanks, elements | $285 – $550 | Swell Guy Plumbing Co. published price ranges · 2026 |
Every row above is published by a company operating in this metro, on its own website. ⚠️ One of them publishes two different tankless ranges on two different live pages, which is a useful reminder that a published range is a starting point and not a quote.
| Job | Published price | Source |
|---|---|---|
| Tankless, installed — all fuels | $1,400 – $5,600 | HomeGuide — tankless water heater installation cost · 2026 |
| Tankless, installed — natural gas | $2,100 – $5,600 | HomeGuide — tankless water heater installation cost · 2026 |
| Tankless, installed — electric | $1,400 – $3,000 | HomeGuide — tankless water heater installation cost · 2026 |
| Tankless, installed | $1,200 – $3,500, averaging $2,800 | This Old House — tankless water heater installation cost · 2026-06-12 — updated 12 June 2026 |
| Tankless, installed | $2,500 – $4,500, averaging $2,811 | Fixr — install a tankless water heater · 2025-01-31 — last updated January 2025 |
| Tankless gas, installed | $3,293 – $3,859 | Homewyse — cost to install a tankless gas water heater · 2026-05 — May 2026, 8.5 gpm at 35°F rise |
| Tankless, installed — North Charleston SC specifically | $1,512 – $2,837, averaging $2,080 | Angi — how much does a tankless water heater cost · 2026-08-03 — Angi’s own localised range, updated 3 August 2026 |
| Tank water heater, installed | $600 – $3,100 | HomeGuide — water heater installation cost · 2026 |
⚠️ Read these with the dates. Fixr’s page was last modified in January 2025 and several widely-cited guides are older still — Bob Vila’s in 2023 and Forbes Home’s in 2024 — which is why they are not on this page. Angi publishes a North Charleston figure specifically, and it lands below every other range here, which is consistent with South Carolina plumbing labour running below the national average.
| Item | Published range | Source |
|---|---|---|
| Upsizing the gas line from 1/2 in. to 3/4 in. | $400 – $800 | This Old House — tankless water heater installation cost · 2026-06-12 |
| Larger-diameter gas supply line, or a new gas line entirely | $350 – $2,000 | HomeGuide — tankless water heater installation cost · 2026 |
| New stainless or PVC venting through wall or roof | $400 – $800 | This Old House — tankless water heater installation cost · 2026-06-12 |
| Replacing the vent — the tank’s vent cannot be reused | $100 – $600 | HomeGuide — tankless water heater installation cost · 2026 |
| Venting where none existed | $500 – $1,500 | HomeGuide — water heater installation cost · 2026 |
| A dedicated 240 V circuit | $250 – $900 | HomeGuide — tankless water heater installation cost · 2026 |
| Panel upgrade, 100 A to 200 A | $1,300 – $1,600 | HomeGuide — cost to replace an electrical panel · 2026 |
| Removing and disposing of the old heater | $75 – $500 | HomeGuide — tankless water heater installation cost · 2026 |
| Isolation valve kit | $60 – $110 for the brass | Angi — how much does a tankless water heater cost · 2026-08-03 |
HomeGuide puts the unit itself at only 40% to 45% of the total project cost (HomeGuide — tankless water heater installation cost), and a non-condensing unit at about 25% less to install than a condensing one. That is the whole story of a tankless quote in one line: you are mostly not buying the appliance.
A whole-house gas unit runs about 199,900 BTU/h against 40,000 BTU/h for a typical 40-gallon tank. Rheem’s instruction to installers is to read the rating plate on your meter and call the gas company if the total demand for the house exceeds it (Rheem tankless use & care manual with installation instructions).
A meter upgrade is the utility’s work, not the plumber’s, and it has its own lead time. It is the item most likely to move a job by weeks rather than by dollars.
The flue from the tank cannot be reused. A condensing unit is a Category IV appliance venting cool, acidic exhaust under positive pressure through sealed PVC or stainless, and it produces liquid condensate that has to be drained. Published ranges put the vent at $400 to $800, or $500 to $1,500 where no suitable route exists.
This is the single cleanest local figure on the page. The same Charleston company publishes $2,850 to $4,500 for a new tankless installation and $1,950 to $3,800 to replace an existing one — roughly a $900 difference that is the gas line and the vent already being there.
Charleston Water System has fitted a dual check valve to every residential service since 1985, in its own words (Charleston Water System Cross Connection Control Program Manual EC-CC-00016). That makes the house a closed system, and thermal expansion has to go somewhere.
The code language on expansion control is written around storage water heaters, so on a tankless unit it is your building official and the manufacturer’s instructions that settle it. What it is not is a surprise line item to discover after the fact — ask for it to be addressed on the quote either way.
A garage wall near the gas line, near the main and near an outside wall for the vent is the cheap version. An interior closet with a long vent run, an attic, or a crawl space is not. Vent length is limited and every elbow spends some of the allowance, so the mounting position is a price decision before it is an aesthetic one.
| Jurisdiction | Published fee | Source |
|---|---|---|
| City of Charleston | Plumbing: $40 application plus $3.50 a fixture. Fuel gas: $40 application plus $10 for one to four outlets. | City of Charleston building and trade permit fee schedule · eff. 2019-10-01 |
| City of North Charleston | $30 filing fee, plus $3.50 for each water heater and/or vent, plus $10 fuel gas for one to four outlets. | City of North Charleston permit fees · 2026 |
| Berkeley County | $5.00 for each water heater and appurtenances, $15 for water piping. | Berkeley County Code §11-88 · 2026 |
| York County | $17 minimum on work valued at $1,000 or less. | York County residential permit fees · 2026-07 |
| Town of Fort Mill | $25 on work valued at $1,000 or under. | Town of Fort Mill fee schedule · FY2025-26 |
North Charleston is the only jurisdiction in either metro whose published schedule has a water-heater line on it. The permit is never the expensive part; the inspection is what protects you if the unit fails and an insurer asks who fitted it.
We contract the job as the general contractor: scope, schedule, the licensed plumbing subcontractor, the permit and the inspection. You get one written price for the whole job before anything starts, and the gas line, the vent and the condensate appear on it as their own lines rather than disappearing into a single number.
Before we quote, we establish three things at the house: whether there is gas and what the meter is rated at, what the panel can carry if the answer is electric, and where the unit can be mounted so the vent run is short. Those three determine most of the price, and none of them can be settled over the phone.
And if the honest answer is that your working tank should be left alone for another two years, or that a heat pump water heater fits your all-electric house better than anything we would fit on this page, that is what we will tell you.
Published local prices run $2,850 to $4,500 for a new gas installation and $1,950 to $3,800 to replace an existing tankless unit. A Summerville company publishes $3,000 to $6,500 and up for a whole-home unit.
Angi publishes a North Charleston specific range of $1,512 to $2,837 averaging $2,080, which sits below the national figures and is consistent with South Carolina plumbing labour running below the national average. The spread between those numbers is mostly about whether the gas line and the vent are new work.
Because the appliance is only 40% to 45% of the project. A 50-gallon tank replacement is published locally at $1,550 to $2,800; a new gas tankless installation at $2,850 to $4,500.
The gap is the gas supply, the vent and the condensate. A whole-house gas tankless unit is rated around 199,900 BTU per hour against about 40,000 for the tank it replaces, so the gas line is resized and the meter capacity checked, and the old flue cannot be reused because a condensing unit exhausts cool acidic gas and liquid condensate.
The conversion itself — beyond the unit and the basic labour — is typically $400 to $800 to upsize the gas line from half-inch to three-quarter, $400 to $800 for new venting, and $75 to $500 to remove and dispose of the old heater.
Where a gas line has to be run further or a new one installed, the published range goes to $2,000, and a Charleston company publishes gas line installation from $750 with a 50-foot minimum. On the electric side the equivalent item is the panel: $1,300 to $1,600 to go from 100 to 200 amps.
$185 for a descaling flush and $249 for a flush with a filter check and safety inspection, both published by Charleston-area companies. National guides say $150 to $350.
Charleston’s water is soft — the utility publishes about 54 to 58 ppm and calls it moderately soft, against a Noritz warranty threshold of 12 grains — so the rate at which scale forms here is low. That is a reason to ask your installer for the correct interval in writing, not a reason to skip the maintenance the warranty is conditioned on.
No. These are prices published by other companies, by manufacturers and by national cost guides, gathered on 13 September 2026, each listed with its source and date.
They are planning ranges, and the spread between them is real rather than sloppy — the same job is published at $2,850 in Charleston and $6,228 in Charlotte. Call (843) 718-8177 and we will price your actual house.
Because the business model is the in-home visit. Across both metros this research found five companies publishing an installed tankless price on their own website; everyone else advertises “upfront pricing” and publishes no number.
The consequence is visible in the search results. Ask Google what a tankless water heater costs in Charleston and it answers using a plumber in Dallas–Fort Worth and a lead-generation page for a town a hundred and ninety miles away, because no Charleston firm gave it anything better to use.
No. The IRS says the Energy Efficient Home Improvement Credit “will not be allowed for any property placed in service after December 31, 2025”.
It was terminated early by P.L. 119-21. A great deal of cost content still advertises the 30% credit, and the ENERGY STAR page most of it links to now returns a 404. Do not let a quote be justified by it.
The licensed plumbing subcontractor pulls it in their own name. The fees are small and published.
The City of Charleston charges a $40 application fee on a plumbing permit and another on a fuel gas permit, plus per-fixture and per-outlet charges. North Charleston charges a $30 filing fee and $3.50 for each water heater and vent. York County starts at $17 and Fort Mill at $25 on work valued under $1,000. The permit is never the expensive part.
Charleston, Mount Pleasant, North Charleston, Summerville, Goose Creek, James Island, West Ashley, Daniel Island, Johns Island, Hanahan, Ladson, Moncks Corner, Isle of Palms, Folly Beach, Park West — across the Charleston Lowcountry and York County, South Carolina.
Southeastern Renovation contracts the job as the general contractor. The plumbing and gas work is performed by licensed plumbing subcontractors who pull their own trade permits.
Part of Southeastern Renovation's plumbing division. Charleston's water chemistry is covered in more depth by the water treatment division.